Yes indeed, with HotRod it is sufficient to give at least the coordinates of one endpoint in the cluster, and it will receive the topology (i.e. server node addresses) automatically.
The addCluster() method in the RemoteCacheManager ConfigurationBuilder is for configuring backup site failover, so that if your primary cluster goes down, the clients can be switched to connect to a remote backup site. It has no relation to server groups.
Got it, thanks